I'm stuck with how to find the buoyancy force on an object.

 

I know how to find density but I can't find it in my textbook how to find the buoyancy force.

 

 

Could someone help with the general idea of finding the buoyancy force? I don't need the answer, just what equation I should be using for this.

 

Thanks.

there are two ways of doing this

 

1/ you can do a differential force balance by considering the geometry of the object and the respective depths(this is only practical for simple shapes as it can get very complicated very quickly)

 

2/ you work out the mass of water displaced by the object. the weight of this displaced water will be equal to the buoyancy force.

Okay, didn't understand the first one, so for the second one.

 

If the mass of the object is 180 kg - then the weight is f = mg or f = 180 kg * 9.8m/s^2 = 17287.2 N.

 

Is that correct? I'm so lost.

How much volume does the object displace? (You can get this from the mass and density)

 

The weight of water of that volume is the buoyant force.

flyguy,

 

for the second choice, look up "Archimedes' Principle" in your favorite Internet search Engine

Thanks for the help everyone.

 

So F = dvg.

 

Thanks for all the help. See ya around.